A collection of nearly 10 million stars, Omega Centauri is the largest of about 150 “globular clusters” in the Milky Way. The stars’ colors give us information about them. Bright blue stars are old, hot stars that are now burning helium instead of hydrogen in their cores. Bright red stars are cool giants that are heading into old age. Dimmer red stars are cool dwarfs destined to live for a long, long time. White stars are typically middle-aged, average stars.